Seems weird.
It's now ambidextrous, so there are no thumb buttons anymore
They dropped the 5700dpi Laser sensor for a 2500dpi optical sensor
By the looks of the "screenshot" the Software changed... again

What's going on at Logitech?
I can't wait to see it at a local store so I can hold and feel it...

The sensor is too far back and off centre, especially for an optical mouse. To be quite honest, most of those auxiliary buttons will be pretty useless for most people. They put far too many useless buttons on it in an attempt to make it ambidextrous and took away the all important thumb buttons in the process.

This seems like a desperate attempt at the budget market, it seems Logitech really was in desperate need of new management.